GCHQ insisted it operated within a “strict legal and policy framework”.

The Intelligence and Security Committee will receive a report on claims it received material through the secret Prism scheme “very shortly”, according to chairman Sir Malcolm Rifkind.

Prism, set up by the US National Security Agency, appeared to allow GCHQ to circumvent the formal legal process required to obtain personal material, such as emails, photographs and videos from internet companies based outside the UK.

GCHQ insisted it operated within a “strict legal and policy framework”.